<!DOCTYPE html>
<div>crbug.com/417064 minimal reproduction case for hitting assertion check</div>
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<script>
if (window.testRunner)
    testRunner.dumpAsText();

var tapme = document.querySelector('#tapme');

tapme.addEventListener('mouseup', function() {
    tapme.attachShadow({mode: 'open'});
}, false);

if (window.eventSender) {
    eventSender.gestureTap(tapme.offsetLeft + tapme.offsetWidth / 2, tapme.offsetTop + tapme.offsetHeight / 2);
}
</script>
